1. Field of the Invention (Technical Field)
The present invention relates to safety devices for preventing tampering or accidental change of the manually set position of a rotatable shaft, such as the shaft on a valve or regulator that controls the flow of fluid.
2. Background Art
Present lockout devices are designed to lock the handle on a valve or regulator where the handle is part of the original valve or regulator supplied by the manufacturer. Typically in these lockout devices, an enclosure is formed around the handle with a padlock that locks the enclosure in place to prevent access to the handle thus preventing the rotational position setting of the handle from being altered either accidentally or out of ignorance or maliciousness. Other lockout devices show a lock assembly that is housed within a cast valve body that with the aid of a key controls rotation of the valve shaft.
Examples of such locks are shown in U.S. Pat. Nos. 440,714 (Lamb), 441,357 (Crowell), 1,154,389 (Fogalsong), 1,248,204 (Thomsen), 1,250,127 (Beers), 1,380,675 (Myers), 1,526,047 (Butterworth), 1,672,137 (Seng), 1,843,072 (Stone), 2,795,129 (Schoepe), 3,134,291 (Barry), 5,085,063 (Van Dyke). Additional patents were cited in the prosecution of the parent application from which this application is a continuation-in-part.
The principal objection to all of the above-identified lockout devices is the complexity of the mechanism which causes problems in reliability, increased manufacturing cost, and thus an increased price. Furthermore, many of these lockout devices require that the valve or regulator body handle be specially cast so as to house the locking assembly. Accordingly, the locking device is part of the valve or regulator when purchased and each valve or regulator manufacturer may have different types of devices which prevents uniformity of a single lockout device used throughout a manufacturing plant. It would be highly desirable to have a lockout device that could be used for a wide variety of different manufacturers"" valves or regulators so that plant personnel could be taught to operate a single type of lockout device even though valves and regulators from different manufacturers are used in the same industrial plant.
Additionally, the prior art does not address the problem posed to industrial plant managers attempting to comply with regulations of the Occupational Safety and Health Act (OSHA). In particular, in 29 C.F.R. xc2xa7 1910.147, the regulations set forth the responsibility of a plant operator for the control of hazardous energy. These devices are typically referred to as xe2x80x9clockout/tagoutxe2x80x9d devices. The purpose, as set forth in the regulations, is to prevent the xe2x80x9cunexpected energization or start-up of the machines or equipment, or release of stored energy that could cause injury to employees undertaking servicing and maintenance of machines and equipment in the plant.xe2x80x9d According to the regulations, xe2x80x9clockoutxe2x80x9d requires the xe2x80x9cplacement of a lockout device on an energy-isolating device, in accordance with an established procedure, insuring that the energy-isolating device and the equipment being controlled cannot be operated until the lockout device is removed.xe2x80x9d Such safety lockout device requires some personnel-controlled means for locking, or operation. The regulation further provides that safety lockout devices shall be standardized within the facility with respect to color, shape, or size.
An important feature of the safety lockout procedure is that the safety lockout device must be under the exclusive control of the authorized employee performing the servicing or maintenance. Accordingly, it is understood that compliance with these regulations will require that a safety lockout device has at least one key, or combination, that can be used only by the authorized service/maintenance person to override any other lockout device that otherwise may be applied to the energy-controlling device.
Of additional concern, especially in large facilities where multiple handles are in place, is the task of key management. A keyless lock removes the necessity of a key to unlock the handle, while still maintaining restricted access through a user-supplied padlock or other lock upon the surrounding cap.
If it is desirable to have a lockout device to maintain a rotatable shaft in a fixed manual setting, during normal operation of the plant, there may be provided an xe2x80x9coperationsxe2x80x9d lockout device that is available to the process control engineer, supervisor, or other employee responsible for establishing the settings on all energy-controlling devices. The OSHA or xe2x80x9cservice/maintenancexe2x80x9d or xe2x80x9csafetyxe2x80x9d or xe2x80x9cpersonalxe2x80x9d lockout device then must supercede this operations lockout device so that a second keyed or combination lock under the exclusive control of service personnel can be applied to prevent access to the operations lockout device.
The present invention is a keyless locking mechanism for use in a lockout device for preventing the rotation of a shaft from a first rotational position comprising a substantially cylindrical body for insertion into an opening in the lockout device, a bearing chamber horizontally disposed within the cylindrical body, a plurality of bearings, preferably two bearings, disposed within the bearing chamber, a spring positionally disposed between the bearings, and an activator slot disposed on the top of the cylindrical body. Preferably, the keyless locking mechanism further comprises a viewing aperture positionally next to the activator slot for determining operational engagement of the mechanism.
The invention is also a lockout device for preventing the rotation of a shaft from a first rotational position comprising a handle body, a gear rotatably supported by the handle body and fixed to the shaft, a core positionally fixed to the gear, and a keyless locking mechanism comprising a spring-bearing mechanism disposed within the top of the handle body. Preferably, the gear comprises a sprocket gear having teeth directed radially outward from the axis of the handle body. Alternatively, the gear comprises a ring gear having teeth directed radially inward toward the axis of the handle body. In a preferred embodiment, the spring-bearing mechanism is disposed horizontally within the keyless locking mechanism. Preferably, the bearings extent to engage indents of the gear teeth to positionally fix rotation. In a preferred embodiment, the lockout device comprises a ratchet wheel fixedly secured to the ring gear or sprocket gear, and a spring-based pawl mounted in the handle body lower end opening for selective engagement with the ratchet whereby when the handle body is not fixed with the ring gear or sprocket gear, the handle body may be rotated in one direction only. The lockout device preferably further comprises a second locking device selectively engageable with the handle body for blocking access to the first locking device when the second locking device is engaged. Preferably, the second locking device comprises an enclosure fitting around at least a portion of the handle body to cover the first locking device and selectively locked to the handle body by a padlock. Alternatively, the second locking device comprises an extension for receiving a plurality of personal locking devices selectively mountable on and lockable to the handle body.
A primary object of the present invention is to provide a simple, low-cost, highly reliable, compact, lockout device for use on a wide variety of rotatable shaft control devices, such as valves, regulators and the like.
Another object of the present invention is to provide a lockout device which when in the locked position will still allow the rotatable shaft to be rotated in one direction only, such as to close the setting of the shaft of the control device but not to allow opening of the control device.
Still another object of the present invention is to provide a lockout device that complies with the Occupational Safety and Health Administration requirements for plant safety.
Still one more object of the present invention is to provide a lockout device having two lockout mechanisms; the first mechanism being in the control of plant personnel responsible for the operation of the process including the setting of various valves, regulators, and other energy-controlling devices having a rotatable shaft wherein the operations lockout device includes a keyless lock mechanism to permit such personnel to manually set the position of a rotatable shaft so as to control the amount of energy passing through a device; and a second, keyed or combination safety lockout device that is under the exclusive control of a service or maintenance person and which overrides the operations lockout device so as to prevent any inadvertent release of energy while the service person is working on the equipment.
One more object of the present invention is to provide a lockout device that is equally usable on a wide range of different manufacturers"" valves, regulators, or other energy control devices so that within a single industrial facility, although valves and regulators from different manufacturers are used, a single type of lockout device may be employed, thus conforming with one of the requirements of the OSHA regulations, and also facilitating the proper use of such lockout devices by authorized personnel.
An additional object of the present invention is to eliminate the need for separate keys for each lockout device.
A primary advantage of the present invention is the ability to control access to limited individuals.
Another advantage of the present invention is to provide easy access to a large number of valves or regulators.
Still another advantage of the present invention is the adaptability of the keyless lock to a variety of manufacturers"" valves, regulators, or energy control devices, without modification.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.